The common infectious shellfish diseases are problematic causing important ecological and economical impacts. Although they have been extensively studied, the dynamics of infection require an innovative approach to disease modeling in order to understand the determinants of epizootics. We developed a single population marine infectious disease model SIIPS (Susceptibles, Infecteds, and Infective Particles in Space) of the Kermack-McKendrick type, sufficiently flexible to study the dynamics of a wide range of shellfish diseases caused by different pathogens such as bacteria, fungi, protozoan parasites and viruses. We used the model to investigate the eastern oyster Crassostrea virginica and the protozoan parasite Perkinsus marinus host-pathogen system. SIIPS is mainly structured around transmission and death rates of the parasite and filtration, mortality and recruitment rates of the oyster. We simulated realistic cases using, when possible, initial conditions and parameter values adopted from previous studies and experiments specifically carried out for this study. The parameters exerting the most influence on simulation outcomes such as the time-history of Dermo prevalence and oyster mortality were identified through a sensitivity analysis carried out using Monte Carlo algorithm. The transmission rate, the infective dose, and natural and disease mortality rates are the major factors shaping the outcome of the disease process in oyster population dynamics. Parameters less well studied such as the release rate of pathogen cells from infected oysters and the rate of cell inactivation in vivo were also identified as influential. Overall, SIIPS performed adequately and proved to be a suitable tool for studying the Dermo-oyster system dynamics.